static void DoStatement (void)
/* Handle the 'do' statement */
{
/* Get the loop control labels */
unsigned LoopLabel = GetLocalLabel ();
unsigned BreakLabel = GetLocalLabel ();
unsigned ContinueLabel = GetLocalLabel ();
/* Skip the while token */
NextToken ();
/* Add the loop to the loop stack */
AddLoop (BreakLabel, ContinueLabel);
/* Define the loop label */
g_defcodelabel (LoopLabel);
/* Parse the loop body */
Statement (0);
/* Output the label for a continue */
g_defcodelabel (ContinueLabel);
/* Parse the end condition */
Consume (TOK_WHILE, "`while' expected");
TestInParens (LoopLabel, 1);
ConsumeSemi ();
/* Define the break label */
g_defcodelabel (BreakLabel);
/* Remove the loop from the loop stack */
DelLoop ();
}
static void WhileStatement (void)
/* Handle the 'while' statement */
{
int PendingToken;
CodeMark CondCodeStart; /* Start of condition evaluation code */
CodeMark CondCodeEnd; /* End of condition evaluation code */
CodeMark Here; /* "Here" location of code */
/* Get the loop control labels */
unsigned LoopLabel = GetLocalLabel ();
unsigned BreakLabel = GetLocalLabel ();
unsigned CondLabel = GetLocalLabel ();
/* Skip the while token */
NextToken ();
/* Add the loop to the loop stack. In case of a while loop, the condition
** label is used for continue statements.
*/
AddLoop (BreakLabel, CondLabel);
/* We will move the code that evaluates the while condition to the end of
** the loop, so generate a jump here.
*/
g_jump (CondLabel);
/* Remember the current position */
GetCodePos (&CondCodeStart);
/* Emit the code position label */
g_defcodelabel (CondLabel);
/* Test the loop condition */
TestInParens (LoopLabel, 1);
/* Remember the end of the condition evaluation code */
GetCodePos (&CondCodeEnd);
/* Define the head label */
g_defcodelabel (LoopLabel);
/* Loop body */
Statement (&PendingToken);
/* Move the test code here */
GetCodePos (&Here);
MoveCode (&CondCodeStart, &CondCodeEnd, &Here);
/* Exit label */
g_defcodelabel (BreakLabel);
/* Eat remaining tokens that were delayed because of line info
** correctness
*/
SkipPending (PendingToken);
/* Remove the loop from the loop stack */
DelLoop ();
}
static int IfStatement (void)
/* Handle an 'if' statement */
{
unsigned Label1;
unsigned TestResult;
int GotBreak;
/* Skip the if */
NextToken ();
/* Generate a jump label and parse the condition */
Label1 = GetLocalLabel ();
TestResult = TestInParens (Label1, 0);
/* Parse the if body */
GotBreak = Statement (0);
/* Else clause present? */
if (CurTok.Tok != TOK_ELSE) {
g_defcodelabel (Label1);
/* Since there's no else clause, we're not sure, if the a break
** statement is really executed.
*/
return 0;
} else {
/* Generate a jump around the else branch */
unsigned Label2 = GetLocalLabel ();
g_jump (Label2);
/* Skip the else */
NextToken ();
/* If the if expression was always true, the code in the else branch
** is never executed. Output a warning if this is the case.
*/
if (TestResult == TESTEXPR_TRUE) {
Warning ("Unreachable code");
}
/* Define the target for the first test */
g_defcodelabel (Label1);
/* Total break only if both branches had a break. */
GotBreak &= Statement (0);
/* Generate the label for the else clause */
g_defcodelabel (Label2);
/* Done */
return GotBreak;
}
}
void DefaultLabel (void)
/* Handle a default label */
{
/* Default case */
NextToken ();
/* Now check if we're inside a switch statement */
if (Switch != 0) {
/* Check if we do already have a default branch */
if (Switch->DefaultLabel == 0) {
/* Generate and emit the default label */
Switch->DefaultLabel = GetLocalLabel ();
g_defcodelabel (Switch->DefaultLabel);
} else {
/* We had the default label already */
Error ("Multiple default labels in one switch");
}
} else {
/* case keyword outside a switch statement */
Error ("`default' label not within a switch statement");
}
/* Skip the colon */
ConsumeColon ();
}
CodeLabel* CS_GenLabel (CodeSeg* S, struct CodeEntry* E)
/* If the code entry E does already have a label, return it. Otherwise
* create a new label, attach it to E and return it.
*/
{
CodeLabel* L;
if (CE_HasLabel (E)) {
/* Get the label from this entry */
L = CE_GetLabel (E, 0);
} else {
/* Get a new name */
const char* Name = LocalLabelName (GetLocalLabel ());
/* Generate the hash over the name */
unsigned Hash = HashStr (Name) % CS_LABEL_HASH_SIZE;
/* Create a new label */
L = CS_NewCodeLabel (S, Name, Hash);
/* Attach this label to the code entry */
CE_AttachLabel (E, L);
}
/* Return the label */
return L;
}
SymEntry* AddLabelSym (const char* Name, unsigned Flags)
/* Add a goto label to the label table */
{
/* Do we have an entry with this name already? */
SymEntry* Entry = FindSymInTable (LabelTab, Name, HashStr (Name));
if (Entry) {
if (SymIsDef (Entry) && (Flags & SC_DEF) != 0) {
/* Trying to define the label more than once */
Error ("Label `%s' is defined more than once", Name);
}
Entry->Flags |= Flags;
} else {
/* Create a new entry */
Entry = NewSymEntry (Name, SC_LABEL | Flags);
/* Set a new label number */
Entry->V.Label = GetLocalLabel ();
/* Generate the assembler name of the label */
Entry->AsmName = xstrdup (LocalLabelName (Entry->V.Label));
/* Add the entry to the label table */
AddSymEntry (LabelTab, Entry);
}
/* Return the entry */
return Entry;
}
static void WhileStatement (void)
/* Handle the 'while' statement */
{
int PendingToken;
/* Get the loop control labels */
unsigned LoopLabel = GetLocalLabel ();
unsigned BreakLabel = GetLocalLabel ();
/* Skip the while token */
NextToken ();
/* Add the loop to the loop stack. In case of a while loop, the loop head
* label is used for continue statements.
*/
AddLoop (BreakLabel, LoopLabel);
/* Define the head label */
g_defcodelabel (LoopLabel);
/* Test the loop condition */
TestInParens (BreakLabel, 0);
/* Loop body */
Statement (&PendingToken);
/* Jump back to loop top */
g_jump (LoopLabel);
/* Exit label */
g_defcodelabel (BreakLabel);
/* Eat remaining tokens that were delayed because of line info
* correctness
*/
SkipPending (PendingToken);
/* Remove the loop from the loop stack */
DelLoop ();
}
static Literal* NewLiteral (const void* Buf, unsigned Len)
/* Create a new literal and return it */
{
/* Allocate memory */
Literal* L = xmalloc (sizeof (*L));
/* Initialize the fields */
L->Label = GetLocalLabel ();
L->RefCount = 0;
L->Output = 0;
SB_Init (&L->Data);
SB_AppendBuf (&L->Data, Buf, Len);
/* Return the new literal */
return L;
}
static Function* NewFunction (struct SymEntry* Sym)
/* Create a new function activation structure and return it */
{
/* Allocate a new structure */
Function* F = (Function*) xmalloc (sizeof (Function));
/* Initialize the fields */
F->FuncEntry = Sym;
F->ReturnType = GetFuncReturn (Sym->Type);
F->Desc = GetFuncDesc (Sym->Type);
F->Reserved = 0;
F->RetLab = GetLocalLabel ();
F->TopLevelSP = 0;
F->RegOffs = RegisterSpace;
F->Flags = IsTypeVoid (F->ReturnType) ? FF_VOID_RETURN : FF_NONE;
/* Return the new structure */
return F;
}
void SwitchStatement (void)
/* Handle a switch statement for chars with a cmp cascade for the selector */
{
ExprDesc SwitchExpr; /* Switch statement expression */
CodeMark CaseCodeStart; /* Start of code marker */
CodeMark SwitchCodeStart;/* Start of switch code */
CodeMark SwitchCodeEnd; /* End of switch code */
unsigned ExitLabel; /* Exit label */
unsigned SwitchCodeLabel;/* Label for the switch code */
int HaveBreak = 0; /* True if the last statement had a break */
int RCurlyBrace; /* True if last token is right curly brace */
SwitchCtrl* OldSwitch; /* Pointer to old switch control data */
SwitchCtrl SwitchData; /* New switch data */
/* Eat the "switch" token */
NextToken ();
/* Read the switch expression and load it into the primary. It must have
* integer type.
*/
ConsumeLParen ();
Expression0 (&SwitchExpr);
if (!IsClassInt (SwitchExpr.Type)) {
Error ("Switch quantity is not an integer");
/* To avoid any compiler errors, make the expression a valid int */
ED_MakeConstAbsInt (&SwitchExpr, 1);
}
ConsumeRParen ();
/* Add a jump to the switch code. This jump is usually unnecessary,
* because the switch code will moved up just behind the switch
* expression. However, in rare cases, there's a label at the end of
* the switch expression. This label will not get moved, so the code
* jumps around the switch code, and after moving the switch code,
* things look really weird. If we add a jump here, we will never have
* a label attached to the current code position, and the jump itself
* will get removed by the optimizer if it is unnecessary.
*/
SwitchCodeLabel = GetLocalLabel ();
g_jump (SwitchCodeLabel);
/* Remember the current code position. We will move the switch code
* to this position later.
*/
GetCodePos (&CaseCodeStart);
/* Setup the control structure, save the old and activate the new one */
SwitchData.Nodes = NewCollection ();
SwitchData.ExprType = UnqualifiedType (SwitchExpr.Type[0].C);
SwitchData.Depth = SizeOf (SwitchExpr.Type);
SwitchData.DefaultLabel = 0;
OldSwitch = Switch;
Switch = &SwitchData;
/* Get the exit label for the switch statement */
ExitLabel = GetLocalLabel ();
/* Create a loop so we may use break. */
AddLoop (ExitLabel, 0);
/* Make sure a curly brace follows */
if (CurTok.Tok != TOK_LCURLY) {
Error ("`{' expected");
}
/* Parse the following statement, which will actually be a compound
* statement because of the curly brace at the current input position
*/
HaveBreak = Statement (&RCurlyBrace);
/* Check if we had any labels */
if (CollCount (SwitchData.Nodes) == 0 && SwitchData.DefaultLabel == 0) {
Warning ("No case labels");
}
/* If the last statement did not have a break, we may have an open
* label (maybe from an if or similar). Emitting code and then moving
* this code to the top will also move the label to the top which is
* wrong. So if the last statement did not have a break (which would
* carry the label), add a jump to the exit. If it is useless, the
* optimizer will remove it later.
*/
if (!HaveBreak) {
g_jump (ExitLabel);
}
/* Remember the current position */
GetCodePos (&SwitchCodeStart);
/* Output the switch code label */
g_defcodelabel (SwitchCodeLabel);
/* Generate code */
if (SwitchData.DefaultLabel == 0) {
/* No default label, use switch exit */
SwitchData.DefaultLabel = ExitLabel;
}
g_switch (SwitchData.Nodes, SwitchData.DefaultLabel, SwitchData.Depth);
/* Move the code to the front */
GetCodePos (&SwitchCodeEnd);
MoveCode (&SwitchCodeStart, &SwitchCodeEnd, &CaseCodeStart);
/* Define the exit label */
g_defcodelabel (ExitLabel);
/* Exit the loop */
DelLoop ();
/* Switch back to the enclosing switch statement if any */
Switch = OldSwitch;
/* Free the case value tree */
FreeCaseNodeColl (SwitchData.Nodes);
/* If the case statement was (correctly) terminated by a closing curly
* brace, skip it now.
*/
if (RCurlyBrace) {
NextToken ();
}
}
static void ForStatement (void)
/* Handle a 'for' statement */
{
ExprDesc lval1;
ExprDesc lval3;
int HaveIncExpr;
CodeMark IncExprStart;
CodeMark IncExprEnd;
int PendingToken;
/* Get several local labels needed later */
unsigned TestLabel = GetLocalLabel ();
unsigned BreakLabel = GetLocalLabel ();
unsigned IncLabel = GetLocalLabel ();
unsigned BodyLabel = GetLocalLabel ();
/* Skip the FOR token */
NextToken ();
/* Add the loop to the loop stack. A continue jumps to the start of the
** the increment condition.
*/
AddLoop (BreakLabel, IncLabel);
/* Skip the opening paren */
ConsumeLParen ();
/* Parse the initializer expression */
if (CurTok.Tok != TOK_SEMI) {
Expression0 (&lval1);
}
ConsumeSemi ();
/* Label for the test expressions */
g_defcodelabel (TestLabel);
/* Parse the test expression */
if (CurTok.Tok != TOK_SEMI) {
Test (BodyLabel, 1);
g_jump (BreakLabel);
} else {
g_jump (BodyLabel);
}
ConsumeSemi ();
/* Remember the start of the increment expression */
GetCodePos (&IncExprStart);
/* Label for the increment expression */
g_defcodelabel (IncLabel);
/* Parse the increment expression */
HaveIncExpr = (CurTok.Tok != TOK_RPAREN);
if (HaveIncExpr) {
Expression0 (&lval3);
}
/* Jump to the test */
g_jump (TestLabel);
/* Remember the end of the increment expression */
GetCodePos (&IncExprEnd);
/* Skip the closing paren */
ConsumeRParen ();
/* Loop body */
g_defcodelabel (BodyLabel);
Statement (&PendingToken);
/* If we had an increment expression, move the code to the bottom of
** the loop. In this case we don't need to jump there at the end of
** the loop body.
*/
if (HaveIncExpr) {
CodeMark Here;
GetCodePos (&Here);
MoveCode (&IncExprStart, &IncExprEnd, &Here);
} else {
/* Jump back to the increment expression */
g_jump (IncLabel);
}
/* Skip a pending token if we have one */
SkipPending (PendingToken);
/* Declare the break label */
g_defcodelabel (BreakLabel);
/* Remove the loop from the loop stack */
DelLoop ();
}
void InitLiteralPool (void)
/* Initialize the literal pool */
{
/* Get the pool label */
LiteralPoolLabel = GetLocalLabel ();
}
